Question about compiling context and build system integration

[qobilidop]

P4 doesn't really have a standard build system (to my knowledge), but to properly handle preprocessors like #include and conditionals + macros, a specific compiling context has to be assumed. Clangd (using C++ LSP tool as an example because many other languages don't have to deal with the complexities of complicated preprocessors) solves this problem by standardizing a compilation database (more context here), and integrating with common build systems to generate it automatically. I wonder if something similar is needed for p4analyzer?

Some p4c compiler options that are particularly relevant are the following (similar to C/C++):

• -D can be used to define a macro to be used by the preprocessor.
• -I can be used to add directory to include search path.

These could change how a P4 code should be interpreted. For example, when doing "jump to definition", the definition might be in a #if branch pending on a macro supplied from -D.

[viluon]

We plan to handle this by adding include path and macro definition settings to the VS Code extension. On the analyzer-core side, these settings would then simply seed the preprocessor state, coming in as a Salsa input that the preprocessing steps depend on. This should be general enough to fit whatever build system the user works with. It's also possible to define them in a directory-specific VS Code file (./.vscode/settings.json), so they can be handled by VCS.

We might look into some kind of tighter, build system -specific integration if there's significant interest from the community.

[fruffy]

This is the main blocker (for me at least) for making the analyzer generally applicable. I have been successfully running p4analyzer as part of a Sublime-LSP setup. However, for most programs I get something of this nature:

[crates/analyzer-core/src/lib.rs:251] &pp.errors = [
    (
        (
            FileId(
                Id {
                    value: 1,
                },
            ),
            0..19,
        ),
        "Could not find core.p4",
    ),
    (
        (
            FileId(
                Id {
                    value: 1,
                },
            ),
            52..74,
        ),
        "Could not find v1model.p4",
    ),
]

Is it possible already to provide some form of include argument to the analyzer? I am not sure whether I understood the comment correctly.